Growth factors are a group of naturally occurring proteins or steroid hormones that are capable of stimulating cellular growth, proliferation and cellular differentiation. Growth factors are important for regulating a variety of cellular processes and play an important part in maintaining healthy skin structure and function.
Some types of cells, such as keratinocytes making up the epidermis and dermis of the skin can secret growth factors. However, the concentration of growth factor may be decreased age-relatedly. Since the skin should be fertilized by growth factors theoretically, some cosmetic products or cosmetic treatments nowadays are applying growth factors on the surface of the skin, in which the growth factors are extracted from the subject in need thereof. The cosmetic effects which are expected by applying growth factors on the skin surface include but not limited to: reducing the fine lines, expression lines and wrinkles as a result of new collagen synthesis; reducing the dark spots and pigmentation; improving the density, smoothness and firmness; and reducing the uneven skin texture and tone.
Platelet rich plasma (PRP) extracted from the subject in need thereof is used for growth factor treatment. However, the PRP must be used freshly, and cannot be stored for a long period of time. The average life span of platelets is typically only 5 to 9 days after extraction. In skin-care products, growth factors would be used repeatedly, and possibly over long periods of time. A normal cosmetic treatment of growth factors requires several times of treatments spanning a period of 3 to 6 months. Typically, every time before receiving treatment, the subject in need thereof has to suffer venipuncture and wait for at least 30 minutes for the PRP to be extracted. Some products use additives such as preservative or other chemical to extend the shelf life of growth factors.
Moreover, the absorption of the applied growth factors on the skin surface may not be as well as expected because of the block of epidermis. In addition, the PRP treatment known in the art does increase the number of platelets surrounding skin cells, but only a small amount of growth factors can be released from platelets at a slow rate.
It is necessary to provide no-additive and stable growth factors self-provided by the subject in need with a high released concentration and a longer shelf life.